About J1808-1517
J1808-1517 is an uncommon pulsar. It spins once every 544.549 ms, has a dispersion measure of 205 pc cm⁻³ and carries a surface magnetic field around 1.22×10^12 G.
The collapsed core of a star that exploded: about one and a half Suns of matter crushed into a ball the size of a city, held up only by the refusal of neutrons to be squeezed further.